1. Field of the Invention
The present invention relates to an actuator for a fuel injector of an engine of an automobile.
2. Description of the Related Art
Known in the art is an actuator for a fuel injector whereby the fuel injector is controlled by operating a piston through a piezoelectric element, to change the pressure in a cylinder chamber defined by the piston. In such a known actuator for a fuel injector, the piston is pre-loaded, for example, as disclosed in Japanese Unexamined Patent Publication (Kokai) No. 59-206668, by providing a flat spring or other form of compression spring inside the cylinder chamber.
However, if a flat spring or coil spring is used to pre-load the piston, an offset load will be imposed on the piezoelectric element, and as a result, the problems of damage to the piezoelectric element and of an increase in the number of components will arise.